/**
 * This code is mostly from the old Etherpad. Please help us to comment this code. 
 * This helps other people to understand this code better and helps them to improve it.
 * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
 */

// THIS FILE IS ALSO AN APPJET MODULE: etherpad.collab.ace.linestylefilter
// %APPJET%: import("etherpad.collab.ace.easysync2.Changeset");
// %APPJET%: import("etherpad.admin.plugins");
/**
 * Copyright 2009 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// requires: easysync2.Changeset
// requires: top
// requires: plugins
// requires: undefined

var Changeset = require('/Changeset');
var plugins = require('/plugins').plugins;
var map = require('/ace2_common').map;

var linestylefilter = {};

linestylefilter.ATTRIB_CLASSES = {
  'bold': 'tag:b',
  'italic': 'tag:i',
  'underline': 'tag:u',
  'strikethrough': 'tag:s'
};

linestylefilter.getAuthorClassName = function(author)
{
  return "author-" + author.replace(/[^a-y0-9]/g, function(c)
  {
    if (c == ".") return "-";
    return 'z' + c.charCodeAt(0) + 'z';
  });
};

// lineLength is without newline; aline includes newline,
// but may be falsy if lineLength == 0
linestylefilter.getLineStyleFilter = function(lineLength, aline, textAndClassFunc, apool)
{

  var plugins_ = plugins;

  if (lineLength == 0) return textAndClassFunc;

  var nextAfterAuthorColors = textAndClassFunc;

  var authorColorFunc = (function()
  {
    var lineEnd = lineLength;
    var curIndex = 0;
    var extraClasses;
    var leftInAuthor;

    function attribsToClasses(attribs)
    {
      var classes = '';
      Changeset.eachAttribNumber(attribs, function(n)
      {
        var key = apool.getAttribKey(n);
        if (key)
        {
          var value = apool.getAttribValue(n);
          if (value)
          {
            if (key == 'author')
            {
              classes += ' ' + linestylefilter.getAuthorClassName(value);
            }
            else if (key == 'list')
            {
              classes += ' list:' + value;
            }
            else if (key == 'start')
            {
              classes += ' start:' + value;
            }
            else if (linestylefilter.ATTRIB_CLASSES[key])
            {
              classes += ' ' + linestylefilter.ATTRIB_CLASSES[key];
            }
            else
            {
              classes += plugins_.callHookStr("aceAttribsToClasses", {
                linestylefilter: linestylefilter,
                key: key,
                value: value
              }, " ", " ", "");
            }
          }
        }
      });
      return classes.substring(1);
    }

    var attributionIter = Changeset.opIterator(aline);
    var nextOp, nextOpClasses;

    function goNextOp()
    {
      nextOp = attributionIter.next();
      nextOpClasses = (nextOp.opcode && attribsToClasses(nextOp.attribs));
    }
    goNextOp();

    function nextClasses()
    {
      if (curIndex < lineEnd)
      {
        extraClasses = nextOpClasses;
        leftInAuthor = nextOp.chars;
        goNextOp();
        while (nextOp.opcode && nextOpClasses == extraClasses)
        {
          leftInAuthor += nextOp.chars;
          goNextOp();
        }
      }
    }
    nextClasses();

    return function(txt, cls)
    {
      while (txt.length > 0)
      {
        if (leftInAuthor <= 0)
        {
          // prevent infinite loop if something funny's going on
          return nextAfterAuthorColors(txt, cls);
        }
        var spanSize = txt.length;
        if (spanSize > leftInAuthor)
        {
          spanSize = leftInAuthor;
        }
        var curTxt = txt.substring(0, spanSize);
        txt = txt.substring(spanSize);
        nextAfterAuthorColors(curTxt, (cls && cls + " ") + extraClasses);
        curIndex += spanSize;
        leftInAuthor -= spanSize;
        if (leftInAuthor == 0)
        {
          nextClasses();
        }
      }
    };
  })();
  return authorColorFunc;
};

linestylefilter.getAtSignSplitterFilter = function(lineText, textAndClassFunc)
{
  var at = /@/g;
  at.lastIndex = 0;
  var splitPoints = null;
  var execResult;
  while ((execResult = at.exec(lineText)))
  {
    if (!splitPoints)
    {
      splitPoints = [];
    }
    splitPoints.push(execResult.index);
  }

  if (!splitPoints) return textAndClassFunc;

  return linestylefilter.textAndClassFuncSplitter(textAndClassFunc, splitPoints);
};

linestylefilter.getRegexpFilter = function(regExp, tag)
{
  return function(lineText, textAndClassFunc)
  {
    regExp.lastIndex = 0;
    var regExpMatchs = null;
    var splitPoints = null;
    var execResult;
    while ((execResult = regExp.exec(lineText)))
    {
      if (!regExpMatchs)
      {
        regExpMatchs = [];
        splitPoints = [];
      }
      var startIndex = execResult.index;
      var regExpMatch = execResult[0];
      regExpMatchs.push([startIndex, regExpMatch]);
      splitPoints.push(startIndex, startIndex + regExpMatch.length);
    }

    if (!regExpMatchs) return textAndClassFunc;

    function regExpMatchForIndex(idx)
    {
      for (var k = 0; k < regExpMatchs.length; k++)
      {
        var u = regExpMatchs[k];
        if (idx >= u[0] && idx < u[0] + u[1].length)
        {
          return u[1];
        }
      }
      return false;
    }

    var handleRegExpMatchsAfterSplit = (function()
    {
      var curIndex = 0;
      return function(txt, cls)
      {
        var txtlen = txt.length;
        var newCls = cls;
        var regExpMatch = regExpMatchForIndex(curIndex);
        if (regExpMatch)
        {
          newCls += " " + tag + ":" + regExpMatch;
        }
        textAndClassFunc(txt, newCls);
        curIndex += txtlen;
      };
    })();

    return linestylefilter.textAndClassFuncSplitter(handleRegExpMatchsAfterSplit, splitPoints);
  };
};


linestylefilter.REGEX_WORDCHAR = /[\u0030-\u0039\u0041-\u005A\u0061-\u007A\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u00FF\u0100-\u1FFF\u3040-\u9FFF\uF900-\uFDFF\uFE70-\uFEFE\uFF10-\uFF19\uFF21-\uFF3A\uFF41-\uFF5A\uFF66-\uFFDC]/;
linestylefilter.REGEX_URLCHAR = new RegExp('(' + /[-:@a-zA-Z0-9_.,~%+\/\\?=&#;()$]/.source + '|' + linestylefilter.REGEX_WORDCHAR.source + ')');
linestylefilter.REGEX_URL = new RegExp(/(?:(?:https?|s?ftp|ftps|file|smb|afp|nfs|(x-)?man|gopher|txmt):\/\/|mailto:|www\.)/.source + linestylefilter.REGEX_URLCHAR.source + '*(?![:.,;])' + linestylefilter.REGEX_URLCHAR.source, 'g');
linestylefilter.getURLFilter = linestylefilter.getRegexpFilter(
linestylefilter.REGEX_URL, 'url');

linestylefilter.textAndClassFuncSplitter = function(func, splitPointsOpt)
{
  var nextPointIndex = 0;
  var idx = 0;

  // don't split at 0
  while (splitPointsOpt && nextPointIndex < splitPointsOpt.length && splitPointsOpt[nextPointIndex] == 0)
  {
    nextPointIndex++;
  }

  function spanHandler(txt, cls)
  {
    if ((!splitPointsOpt) || nextPointIndex >= splitPointsOpt.length)
    {
      func(txt, cls);
      idx += txt.length;
    }
    else
    {
      var splitPoints = splitPointsOpt;
      var pointLocInSpan = splitPoints[nextPointIndex] - idx;
      var txtlen = txt.length;
      if (pointLocInSpan >= txtlen)
      {
        func(txt, cls);
        idx += txt.length;
        if (pointLocInSpan == txtlen)
        {
          nextPointIndex++;
        }
      }
      else
      {
        if (pointLocInSpan > 0)
        {
          func(txt.substring(0, pointLocInSpan), cls);
          idx += pointLocInSpan;
        }
        nextPointIndex++;
        // recurse
        spanHandler(txt.substring(pointLocInSpan), cls);
      }
    }
  }
  return spanHandler;
};

linestylefilter.getFilterStack = function(lineText, textAndClassFunc, browser)
{
  var func = linestylefilter.getURLFilter(lineText, textAndClassFunc);

  var plugins_ = plugins;

  var hookFilters = plugins_.callHook("aceGetFilterStack", {
    linestylefilter: linestylefilter,
    browser: browser
  });
  map(hookFilters, function(hookFilter)
  {
    func = hookFilter(lineText, func);
  });

  if (browser !== undefined && browser.msie)
  {
    // IE7+ will take an e-mail address like <foo@bar.com> and linkify it to foo@bar.com.
    // We then normalize it back to text with no angle brackets.  It's weird.  So always
    // break spans at an "at" sign.
    func = linestylefilter.getAtSignSplitterFilter(
    lineText, func);
  }
  return func;
};

// domLineObj is like that returned by domline.createDomLine
linestylefilter.populateDomLine = function(textLine, aline, apool, domLineObj)
{
  // remove final newline from text if any
  var text = textLine;
  if (text.slice(-1) == '\n')
  {
    text = text.substring(0, text.length - 1);
  }

  function textAndClassFunc(tokenText, tokenClass)
  {
    domLineObj.appendSpan(tokenText, tokenClass);
  }

  var func = linestylefilter.getFilterStack(text, textAndClassFunc);
  func = linestylefilter.getLineStyleFilter(text.length, aline, func, apool);
  func(text, '');
};

exports.linestylefilter = linestylefilter;